1. Field of the Invention
The present invention relates to inter-vehicle communication apparatuses capable of restricting an inter-vehicle network through which information is exchanged and used among vehicles, with the use of a communication unit mounted on each vehicle, so as not to extend very wide.
2. Description of the Related Art
In recent years, navigation apparatuses have been widely mounted in vehicles, and the navigation apparatuses have been provided with various useful functions. In addition to providing guidance to a destination in the conventional manner, the navigation apparatuses can display information of surrounding facilities, and information of traffic congestion on roads with the use of VICS, and can also automatically provide a detour if a traffic jam occurs on a road.
Since portable telephones have been widely used, various types of information can be obtained in vehicles from the outside. Especially, navigation apparatuses can display necessary data on their screens when they are connected to portable telephones to directly communicate with an information center, or to connect to the Internet to connect to the information center, or to various information-providing sections to receive and use the necessary data.
Further, with the development of communication technologies, communication can be performed between units to exchange data at a frequency band which can be used without a special permission, such as a communication band having a frequency of 2.4 GHz to 2.5 GHz. This is attractive as a means for exchanging data without connecting units by a cable.
When a navigation apparatus is provided with such a communication function, various units mounted in the vehicle, such as a portable telephone, and a program set in advance can be automatically used for communication in a desired manner. In this case, the navigation apparatus can display various types of information sent from the various units on the screen.
When units which can perform communication by the use of a frequency band which can be used without any permission are used in vehicles, communication can be achieved between the units in the vehicles in the same manner as when communication is achieved between a portable telephone and a navigation apparatus. In addition, if an inter-vehicle communication unit is further provided, mutual communication is allowed between the vehicle and another vehicle having a compatible inter-vehicle communication unit and located in the vicinity of the vehicle.
With the use of a program set in advance, mutual communication can be performed automatically under a predetermined condition. When a communication frequency band such as that described above is used, a vehicle having an inter-vehicle communication unit can comminute with other vehicles within a range of about 100 meters from the vehicle in a desired manner free of charge according to a use rule in the frequency band. In this case, depending on program settings, the vehicle can automatically receive predetermined information under a predetermined condition from a vehicle located in the vicinity of the vehicle and having a similar inter-vehicle communication unit, use it, if necessary, and automatically send it to other vehicles.
When such an inter-vehicle automatic communication system is used, a moving vehicle A1 can communicate with other vehicles in a range of about 100 meters from the moving vehicle to collect or exchange various types of information and data, as shown, for example, by an “inter-vehicle communication local network” in FIG. 14. In addition, when a camera is mounted in the vehicle and the camera continuously captures images ahead of the vehicle, other vehicles can take and use the images, if necessary. The inter-vehicle communication network can be used in various ways.
Since the specification of such an inter-vehicle communication local network has not been determined, it can be used in various ways. When a user having the inter-vehicle communication unit wants to subscribe to the network, for example, it is assumed in one case that the user starts operating the inter-vehicle communication unit to prepare for sending the position and the moving direction of the vehicle, the inter-vehicle communication ID, and other information, and, when the network connection is established, enters a basic-information network for exchanging basic information.
Various other optional networks can be prepared in advance, such as a same-driving-path network which includes vehicles moving along the same driving path in the same direction as the local vehicle and vehicles which seem to directly relate to the movement of the local vehicle, and further, a traffic-jam-information network for providing information used in various situations when a traffic jam occurs in the same driving path. In the traffic-jam information network, detour information useful in avoiding the traffic jam can be exchanged. The traffic-jam information network may be one of multiple optional sub-networks in the same-driving-path network, or may be formed as an independent optional network.
When the user wants to subscribe to such an optional network, the user performs an input for network subscription. When the local vehicle has a navigation apparatus and is moving toward the destination, the inter-vehicle communication unit searches for vehicles which have operating inter-vehicle communication units in a range where communications are possible, and which move in the same driving path in the same direction as the local vehicle, or are likely to come to the same driving path, and displays them on a screen. Alternatively, the local vehicle automatically sends and receives necessary information to and from the vehicles.
Further various optional networks can be considered, such as a vehicle-group network which includes vehicles having their vehicle IDs registered in advance, and a surrounding-vehicle network which includes all vehicles located around an intersection and which can be used for all vehicles to pass through the intersection safely. These networks are prepared in advance, and if necessary, such networks can be formed in a desired manner. Since other vehicles also form networks, the user can perform settings according to a setting guidance displayed on the screen before movement or during movement to determine a network to which the vehicle is to subscribe. Therefore, vehicles automatically form optional networks at a predetermined timing.
When the user wants to subscribe to a particular network, the user performs an input for network subscription. As for information specified in advance so as to be used in the network, the information of the user's vehicle is open to all network users, and the user can use the information of the other vehicles in the network in a desired way.
As shown in FIG. 14, a vehicle A4 is in a first-order inter-vehicle communication local network (A1) for the local vehicle A1, the network (A1) existing in a predetermined-distance range where communications are possible around the local vehicle A1, and the local vehicle A1 is in an inter-vehicle communication local network (A4) for the vehicle A4 where the vehicle A4 can perform communications. Therefore, the local vehicle A1 and the vehicle A4 can communicate with each other. Further, the vehicle A4 is in an inter-vehicle communication local network (A6) for a vehicle A6, and the vehicle A6 is in the inter-vehicle communication local network (A4), which is a second-order local network for the local vehicle. Therefore, the vehicle A4 and the vehicle A6 can communicate with each other.
Furthermore, in FIG. 14, through an inter-vehicle communication local network (A6) for the vehicle A6, the vehicle A6 can communicate with a dealer D3 having the same communication unit as the inter-vehicle communication unit. The inter-vehicle communication local network (A6) is a third-order local network for the local vehicle. The dealer 3 forms an independent information transfer system together with dealers D1 and D2 which are in the same group as the dealer 3, and the independent information transfer system includes an information center. Therefore, the vehicle A6 can take various types of information from the information center, and can also use a statistical data base in the information center to obtain a correctly guided path based on the latest traffic information.
With this, the vehicle A4, which is connected to the vehicle A6 through the inter-vehicle communication local networks (A6 and A4), can use the information and data which the vehicle has received from the information center. In addition, the local vehicle A1, which is connected to the vehicle A4 through the inter-vehicle communication local networks (A4 and A1), can use the information and data which the vehicle has received from the information center by the information transfer system, through the vehicle A4, which forms the second-order local network for the local vehicle. By the information transfer system, the local vehicle A1 can directly access the information center to obtain information.
In the case shown in FIG. 14, the information center is connected to the World Wide Web (WWW) on the Internet, and can obtain information through the Internet, if necessary. The Internet users can use the information of the information center. The Internet can be used in vehicles through a portable telephone carried therein, and received information can be displayed on a screen. Therefore, the information of the information center can also be obtained through the Internet.
The local vehicle can obtain various types of information through various networks, and in addition, can automatically obtain information which each vehicle possesses and allows to be made open to the public, by searching. For example, the local vehicle can obtain detailed map data which includes narrow roads, possessed by a particular vehicle to use for route calculations. The local vehicle can also use facility information and resort information collected independently, in the same way as various web sites on the Internet.
As described above, with the use of an inter-vehicle communication unit mounted in each vehicle, the inter-vehicle communication local network of the local vehicle can be connected through the inter-vehicle communication local network of another vehicle which is in the inter-vehicle communication local network of the local vehicle, to still another inter-vehicle communication local network. If a vehicle therein can obtain information from an independent information transfer system, for example, the local vehicle can also use the information.
Further, when one of the networks has an information center therein, the local vehicle can use information and data thereof. When any of the networks can be connected to the Internet, the local vehicle can obtain information on the Internet. Inter-vehicle communication networks form a very broad network in this way, and it is expected that the inter-vehicle communication networks will be further developed and used in various manners, including mutual use of images captured by cameras mounted to vehicles.
When inter-vehicle communication networks such as those described above are used, for example, to form the same-driving-path network among vehicles moving along the same path in the same direction, or to form a traffic-jam network through which predetermined information is mutually transmitted and received when a traffic jam occurs, or when a traffic-jam network serving as a single network is used, the network is formed in a way shown in FIG. 15.
In the case shown in FIG. 15, the local vehicle L3 is moving along a guided path indicated by a driving path G. When the local vehicle L3 indicated by the local vehicle position mark is moving along a road U1, it can form a local network (L3), indicated by a circular communication area, for the local vehicle L3 by a mounted inter-vehicle communication unit.
In the case shown in FIG. 15, the local network (L3) for the local vehicle L3 can physically include a total of seven vehicles, the local vehicle L3, a vehicle L2 moving along the same driving path G and located behind the local vehicle L3, a vehicle L4 moving along the same driving path G and located in front of the local vehicle L3, a vehicle L5 moving along the same driving path G and located beyond an intersection C2 positioned before the vehicle L4, a vehicle R3 moving along the road U1 but in the opposite direction, a vehicle S2 moving from the right in the figure to an intersection C2 along a road W1 intersecting with the road U1, along which the local vehicle L3 is moving, at the intersection C2, and a vehicle S3 moving from the left in the figure to the intersection C2 along the road W1.
When surrounding-vehicle networks are formed around the local vehicle L3, the local vehicle L3 can communicate with vehicles which cannot be seen from the local vehicle L3, and can obtain, for example, camera images therefrom. A person who is likely to suddenly rush out in front of the local vehicle L3 from a place which cannot be seen from the local vehicle because of a building can be observed from the camera images of those vehicles, and some measure can be taken in advance. A plurality of camera images taken at the intersection immediately before the local vehicle can be displayed on a screen in parallel to allow the driver to see the images captured from all directions at the intersection. Therefore, the driver and other passengers can travel in the local vehicle with relief even at intersections where accidents occur frequently.
In the case shown in FIG. 15, the vehicle L4 moving in front of the local vehicle L3 is not provided with an inter-vehicle communication unit used for forming an inter-vehicle network, or it is not using the communication unit (by turning it off, for example) even if the unit is provided. Therefore, this vehicle is not included in any network. Vehicles moving in the direction opposite to the direction in which the local vehicle L3 is moving are not shown in FIG. 15 so as not to make the figure more complicated. For example, one of such vehicles, the vehicle R3, can be included in the inter-vehicle communication network of the local vehicle L3. When it is determined that information sent from the vehicle R3 is rarely used, the vehicle R3 can be set in advance as a vehicle excluded from the network in the same-driving-path network or the traffic-jam network of the local vehicle L3 to automatically exclude the vehicle R3. The vehicle R3 can be included in a drive network for exchanging surrounding-facility information among vehicles surrounding the local vehicle L3.
The local network (L3) of the local vehicle L3 is connected to the local network (L5) of the vehicle L5 moving in front of the local vehicle L3 in the same driving path G. Since the local vehicle L3 is within the local network (L5) of the vehicle L5, the local vehicle L3 and the vehicle L5 can transmit and receive information and data to and from each other. In the local network (L5) of the vehicle L5, a vehicle L7 moving in front of a vehicle L6 which is moving in front of the vehicle L5 has a local network (L7). The vehicles L5 and L7 can transmit and receive information and data to and from each other in the same way.
A vehicle L8 moving in front of the vehicle L7 in the same road past an intersection C3, a vehicle L9 located on a bridge B1 in front of the vehicle L8, and a vehicle L10 moving in front of the vehicle L9 but not reaching an intersection C4 are moving and form respective local networks, and can transmit and receive information and data to and from each other. With this, the local vehicle L3 can obtain the information from the vehicle L10 through the local networks L10, L9, L7, and L3. Therefore, when the local vehicle is going to pass through a certain intersection but does not have detailed map data thereof, the local vehicle can send a request for the map data, search vehicles connected through local networks for a vehicle having the map data, and use it.
When the vehicle L10 has a camera, for example, the local vehicle L3 can obtain images taken by the camera. This means that the congestion or traffic-jam condition of a road can be actually seen on a screen by the use of a camera provided on a vehicle moving far ahead of the local vehicle. Since similar local networks are also formed to the rear of the local vehicle, similar information and the information of the local vehicle can be automatically transferred to vehicles connected to the networks and moving to the rear of the local vehicle. With the use of such camera images, a real bird's eye view can be implemented, in which far-away scenery can be seen. Further, fixed-point observation is also possible in a way in which a specific intersection such as an intersection where the local vehicle is going to turn right is selected, vehicles moving near the intersection are automatically selected, and the camera images of the vehicles are sequentially switched to always display camera images related to the intersection.
When the local vehicle is going to pass through an intersection C2 where a traffic signal is not provided, for example, a vehicle S2 moving from the right in the figure to the intersection and having a local network (S2) can be checked on the screen of the local vehicle by a vehicle mark or other icon, so that the driver can drive through the intersection at a low speed while paying attention. In this way, the state of a vehicle located at a place which cannot be seen can be understood in advance to avoid any dangerous situations during driving.
Such information transfer is possible between four or more wheeled vehicles. In addition, it is also possible between two-wheeled vehicles. When communication units are made compact, pedestrians can carry them. Then, the driver can see a person who may rush out in front of the local vehicle from a place which is out of view, on the screen, to drive the local vehicle safely while paying attention to the person. When pedestrians have such portable communication units for forming local networks, various types of information can be used by using local networks between vehicles such as those described above. Then, in addition to the local networks between vehicles, local networks can be also formed between carried mobile units to allow similar information to be transferred.
When a vehicle S3 is going to turn left at the intersection C2 where a traffic signal is not provided along the road U1 which is now congested, for example, it is possible for the driver of the vehicle S3 to perform actual conversation with the driver of the local vehicle or to send a predetermined signal to the driver of the local vehicle to exchange a request for waiting for a moment from the driver of the vehicle S3 and an affirmative response from the driver of the local vehicle, so that the vehicle S3 can turn left immediately. If the local vehicle were the vehicle S3, the driver of the local vehicle can communicate with the drivers of other vehicles moving along the congested road, so that the local vehicle can turn left smoothly at the intersection having no traffic signal. In the same way, a vehicle can smoothly go into a congested expressway from another road by performing the same communication.
Furthermore, by using the statistical data of information such as that shown in FIG. 14 through the information collection function of another vehicle which can be connected to a local network which includes the information center, various types of information can be obtained, such as specific-road traffic-jam information for certain weather or season, traffic-restriction information when it is snowing, traffic-restriction information when events such as a festival are held, and information of byroads which can be used in a traffic jam or congestion and which are known only to local people. Safe driving is made possible without any wasted time. As for byroads known only to local people, when the driving-path track data of each vehicle is obtained in the same-driving-path network, if a local person uses a byroad in the network, the data of the byroad can be automatically searched for and obtained to share the data.
Japanese Unexamined Patent Application Publication No. 2001-273593 discloses a technology in which communications are performed between an emergency vehicle and general vehicles through a base station to report to the general vehicles that the emergency vehicle is approaching. Japanese Unexamined Patent Application Publication No. Hei-9-7096 discloses a technology in which an emergency vehicle sends a radio signal having a predetermined frequency and general vehicles receive the signal to know that the emergency vehicle is approaching. Japanese Unexamined Patent Application Publications No. Hei-10-153436, No. Hei-10-311730, and No. 2000-20889 disclose technologies in which traffic information is received from the outside.
In an inter-vehicle information network system such as that described above, when a car accident occurs ahead of the local vehicle on the road on which the local vehicle is current moving and the road is blocked, the accident information can be sequentially transmitted from the vehicle which caused the accident or a vehicle which was moving thereafter to the following vehicles.
When such an accident occurs, conventionally, the accident information is collected at a traffic information center, the information is confirmed, and then it is distributed through VICS or broadcasting to an area related to the accident. Therefore, the information is transferred to vehicles moving after the car which caused the accident, but not until some time elapses after the accident occurred.
In contrast, in an inter-vehicle information network system such as that described above, the accident information is transmitted immediately to the following vehicles which will be most affected by the accident.
Even when it is found that the road is blocked by a car accident or other problem, a correct detour to avoid the accident cannot be obtained immediately in vehicles provided with navigation apparatuses using older data, or vehicles provided with navigation apparatuses having a very low calculation speed. Not all vehicles have highly functional navigation apparatuses, which can immediately provide a correct detour for driving. There are many drivers who want to use detour data provided by highly functional navigation apparatuses. Since local people frequently have detailed or special local road information, detours which the local people select are appropriate in many cases. Therefore, it is preferred that the data of such detours be obtained.
When a road is blocked by a car accident, even if detour information is transferred from a vehicle having a highly functional navigation apparatus, the detour is not necessarily appropriate for all following vehicles. The detour is most appropriate for that vehicle, but there may be another appropriate detour for the following vehicles.
In the case shown in FIG. 15, when a vehicle L9 causes a car accident on the bridge B1 to block the bridge B1, a vehicle L7 can search for a detour in which the vehicle L7 turns right at an intersection C3 to move on a road W2, turns left at an intersection C11, passes through a bridge B3, turns left at an intersection C12 to move on a road W3, and turns right at an intersection C4 to return to the driving path G, along which the vehicle L7 was to move. Therefore, when this information is sent to the following vehicle L5, the vehicle L5 can take this appropriate detour based on the information.
The detour information can be sent to and used by the further following local vehicle L3 and the following vehicle L2. In this case, however, the local vehicle L3 can search, by its navigation apparatus, for a detour in which the local vehicle L3 turns left at the intersection C2 to move on the road W1, turns right at an intersection C6, passes through an intersection C7 and a bridge B2, turns right at an intersection C8 to move on a road W3, and turns left at the intersection C4 to return to the driving path G, along which the local vehicle L3 was to move. This detour is shorter than the detour which the vehicle L7 searched for, and hence more appropriate for the local vehicle L3. The following vehicle L2 can use this detour information of the local vehicle L3.
In the same way, a vehicle L1 can use the above-described two pieces of detour information, but can search for a more appropriate detour in which the vehicle L1 turns left at an intersection C1, turns right at an intersection C5, and moves through the detour which the local vehicle L3 found, to immediately avoid the road where the traffic jam occurred. Therefore, the vehicle L1 can immediately move through the detour. This information can be transferred to all vehicles connected through the local networks, but it is meaningless for the vehicle L7, and it is not useful for the local vehicle L3 because it is not appropriate in many cases for the local vehicle L3 to make a U-turn to go back to the intersection C1, and turn right to take the detour which the vehicle L1 found.
In this way, even when local networks can be connected to form a wide network, a network having a restricted area may be preferable depending on the information to be obtained. It is preferred in many cases that the size of a network be restricted for shopping information at nearby stores and neighborhood-event information, in addition to detour information used in the event of a car accident or traffic jam.
To restrict the size of a network, coordinates or road links can, for example, be used, but are not preferable for networks in which network components, such as vehicles, move to change the locations of the networks, because a huge amount of calculation is required.
In addition to an area restriction, such as that applied to an area around the local vehicle, a time restriction, such as that used when the information of events to be held by ten o'clock in the morning of that day is obtained, may be required for a specific network. In such a case, coordinates or road links cannot be used for restriction.
When the user wants to know a detour around a car accident or traffic jam, or when the user wants to form a detour-information network with vehicles surrounding the local vehicle, if the user requests the surrounding vehicles to exchange IDs for forming the network, the surrounding vehicles may respond at a similar time. If there are many surrounding vehicles, the responses therefrom may cause interference, which disables correct receiving and hence disables forming a network. If PN code and IDs are known in advance, a transmission sequence can be determined in advance to avoid the interference. If PN code and IDs are not known, an appropriate action cannot be taken.
After a network forming request is sent to surrounding vehicles, when it is found that there are many vehicles which can respond to the request in the area of the first-order local network in which direct communications with the local vehicle is possible, if forming a network with too many vehicles is not a good idea, the number of vehicles to be included in the first-order local network may be restricted. To this end, means for reducing the number of vehicles which respond at a time to an appropriate number is necessary.
Information exchanges are impossible if PN code and IDs are not known to each other in forming a network. It is not preferred that the PN code and ID of the local vehicle be sent to all surrounding vehicles. Especially when the number of vehicles is to be restricted in the area where direct communications with the local vehicle is possible, it is not necessary to inform all surrounding vehicles of the PN code and ID of the local vehicle. Means for handling this issue is required.